Comparison of cystourethrography and dynamic MRI in bladder neck descent.

Purpose: The purpose of this work was to test whether there are statistically significant differences between dynamic MR and lateral cystourethrogram measurement results in patients with bladder neck descent.

Method: Twenty-seven women (39-83 years old, mean 60.6 years old) with urinary incontinence and bladder neck descent were examined by dynamic MRI using a single shot fast spin echo sequence with half-Fourier data acquisition. Bladder neck position, angle of inclination of the urethral axis, posterior vesicourethral angle, and depth of cystoceles were measured at perineal contraction and at maximal pelvic strain. The nonparametric Wilcoxon test for paired values was used to analyze whether there were statistically significant differences between lateral cystourethrogram and dynamic MR measurement results. The Spearman correlation coefficient (rs) was calculated for all parameter pairs.

Results: Measurements at maximal pelvic strain showed the greatest levels of agreement between MRI and cystourethrography. The best results were attained for the cystocele measurements (p > 0.5, rs = 0.95). Bladder neck position showed the second best agreement; if MR measurements were corrected by 0.46 cm, no statistically significant difference (p > 0.2, rs = 0.92) was calculated. Measurements at perineal contraction tallied least, probably due to the different positions adopted during the two examinations.

Conclusion: Measurement data on dynamic MRI for the bladder neck position and the extension of cystocele at maximal pelvic strain are comparable with lateral cystourethrogram data.